I chose a full-suspension mountain bike frame because the roads and even the bike trails here are so bad. I wanted to isolate the batteries, controller and my butt from the shocks. I also jump off curbs a lot.

I wired pairs of 36-volt Dewalt power tool batteries in series to get 72 volts and then wired each of these pairs in parallel. I can carry two, four, or six battery packs, depending on how long the trip will be.

I replaced my 36-volt, ten-amp controller with a 72-volt, 35-amp version. It also has immediate start, which means the controller does not wait until the wheel is rolling before it puts power to the motor. This lets me get through intersections faster and safer (although I have to be careful or my front wheel lifts off the ground).

I used a rear wheel motor because front wheels here tend to get bent by potholes and fixing one can be expensive if you have a motor mounted in it.
- More info in this article about the project.